1. Technical Field
The present invention relates to an inkjet head, more particularly to a multi-nozzle inkjet print head using an electrostatic field induced type.
2. Description of the Related Art
Inkjet print heads can be classified into, depending on the driving method, a thermal jet type, a piezo type and an electrostatic field induced type. The thermal jet type discharges (ejects) ink by using the expansive force of a bubble generated at the time of heating the ink with a heater. The piezo type discharges ink by using the mechanical vibration or expansive force from a piezoelectric actuator including a piezoelectric material, which is expanded or contracted according to the applied voltage.
Because heating is used, the thermal jet type has limited ink materials and the amount of ejected ink is fixed. The manufacturing cost of the piezo type is higher due to the complicated structure, and the nozzles are often clogged due to the hardening of the ink.
The electrostatic field induced type discharges ink by using the electrostatic attraction induced between electrodes. Compared to the types described above, the electrostatic field induced type has a simpler structure and lower power consumption. However, with the increasing demand for high resolution print quality and high-speed printing, the inkjet print head of the electrostatic field induced type, which has multi-nozzles (that is, a plurality of nozzles), has increasingly suffered with an interference (that is, crosstalk occurrence) caused by an electrostatic field between adjacent nozzles.
High density and high integration of an inkjet print head are indispensable for high resolution print quality and high-speed printing. With regard to this matter, as a separation distance between adjacent nozzles becomes smaller, the electric field interference between adjacent nozzles becomes severer, harming the independent drive of each nozzle. Accordingly, in order to make it possible to independently operate the nozzles at a high speed and to discharge ink to an accurate position, it is necessary that the electric field interference be solved in the inkjet print head of the electrostatic field induced type, which has multi-nozzles.
Additionally, the conventional inkjet print head of the electrostatic field induced type uses a method of applying a driving voltage between a discharge electrode located around the nozzles and a facing electrode located to face the nozzles (see the left-side figures of FIGS. 8a and 8b). However, according to the conventional inkjet print head of the electrostatic field induced type, the facing electrode increases the total size and volume of the apparatus and complicated the connection structure of a driving circuit.